This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A386452 #8 Jul 22 2025 09:51:44
%S A386452 1,1,2,9,71,856,14639,338086,10167592,386920264,18200571057,
%T A386452 1037970049307,70605576249333,5649723531576365,525507834721871564,
%U A386452 56235831305760575845,6861362229615344431713,946930149578851143467375,146781656943702604491445861,25394248429778915431816805711
%N A386452 a(0) = 1; a(n) = a(n-1) + Sum_{k=0..n-1} binomial(k+1,2) * a(k) * a(n-1-k).
%F A386452 G.f. A(x) satisfies A(x) = 1/( 1 - x - x^2 * (d/dx A(x)) - x^3/2 * (d^2/dx^2 A(x)) ).
%o A386452 (PARI) a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=1, n, v[i+1]=v[i]+sum(j=0, i-1, binomial(j+1, 2)*v[j+1]*v[i-j])); v;
%Y A386452 Cf. A075834, A386453, A386454, A386455.
%Y A386452 Cf. A385874.
%K A386452 nonn
%O A386452 0,3
%A A386452 _Seiichi Manyama_, Jul 22 2025